New Iterative (\turbo") Decoding Algorithms

Decoding with feedback or iterative decoding is an eecient, low-complexity means for \informa-tion handover" in any parallel or serial concate-nated coding scheme and in related applications. Invented twenty years ago, it has recently been payed considerable attention in the context of \Turbo Codes". Iterative decoding has been jus-tiied intuitively, but many question remain and perhaps will resist. In this paper, we will revise the conventional turbo decoding scheme proposed by Berrou et al., and investigate alternatives such as maximum-likelihood decoding and iterative decoding using a \Joint-MAP". The alternatives promise slight performance improvements, but at considerable cost. This manifests the excellent original works.